Investors should buy Apple shares predicting the next iPhone's sales will significantly beat expectations, according to JPMorgan, which reiterated its overweight rating.

"We are adding Apple to the AFL [analyst focus list] and materially raising our forecasts due to what we believe is high pent-up replacement demand heading into the 10th anniversary iPhone cycle this year," analyst Rod Hall wrote in a note to clients Sunday. "Multiple iPhone 'Pro' features including 3D facial scanning, a glass heavy design, and a structured-light-enabled camera look likely to us and should drive users to upgrade phones that are older, on average, than they have been for four years."

When the next iPhone launches later this year, the average age of the smartphone for first-time Apple users will be 1.61 years, up from 1.58 years before the iPhone 6 cycle.